How to save chronometer time and retrieve it in another activity using sharedpreferences

Question

I have a chronometer in Mainactivity.java I wanted to save the starting time using SharedPreferences and get the starting time show it in another activity but I can't figure out how to do so .I've tried Service which allows it running in the background but it failed as it can't pass the variable to another activity and people suggested using SharedPreferences would be easier. So does anyone knows how to save the starting time and get the value in another activity? Here's the code.

MainActivity.java

public class MainActivity extends AppCompatActivity{
private Chronometer chronometer;
protected FirebaseAuth firebaseauth = FirebaseAuth.getInstance();

 @Override
      protected void onStart(){
        super.onStart();
          chronometer.setBase(SystemClock.elapsedRealtime());
          final long startTime = (SystemClock.elapsedRealtime() - chronometer.getBase());
          final SharedPreferences pref = PreferenceManager.getDefaultSharedPreferences(this);
          final SharedPreferences.Editor editor = pref.edit();   
              @Override
              public void onDataChange (DataSnapshot dataSnapshot){
                    String status = dataSnapshot.getValue(String.class);

                   if (status.equals ("occupied")) {

                        chronometer.start();
                        editor.putLong("time",startTime);
                       editor.commit();

                   }
                   else
                       mValueView1.setBackgroundColor(Color.parseColor("#66d983"));

              }
              @Override
              public void onCancelled (DatabaseError databaseError){

              }

          });

SecondActivity.java

@Override
    protected void onStart() {
        super.onStart();

        final SharedPreferences pref = PreferenceManager.getDefaultSharedPreferences(this);
        mChildReference1.addValueEventListener(new ValueEventListener() {
            @Override
            public void onDataChange(DataSnapshot dataSnapshot) {
                String status = dataSnapshot.getValue(String.class);
                // firebase status is occupied start chronometer
                if(status.equals("occupied")) {
                   savedTime = pref.getLong("time",01);

                    chronometer.setBase(savedTime);
                    chronometer.getBase();
                    chronometer.setVisibility(View.VISIBLE);


                }

                if(!status.equals("occupied")){
                        chronometer.setBase(SystemClock.elapsedRealtime());
                        pauseOffset = 0;
                        chronometer.stop();

                    }
                }


            @Override
            public void onCancelled(DatabaseError databaseError) {

            }

        });
    }

Mohsen · Answer 1 · 2019-11-09T12:53:53.687

2

if you are using the sharedpreference only in one activity it's ok to use getDefaultSharedPreferences() or getPreferences() methods on your activity.but in your case(as mentioned in the documentation) which is using one sharedPreference for multiple activities, you should assign a name to the sharedpreference.
this way the activity knows to get which of your sharedpreferences. just change this in your code

SharedPreferences pref = getSharedPreferences("chornometer", Context.MODE_PRIVATE);

for more information read the documentation

edited Nov 09 '19 at 12:53

answered Nov 09 '19 at 08:44

Mohsen

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so i just have to change the ```getDefaultSharedPreferences()``` into this? – Anonymous Nov 09 '19 at 10:05
yes, in both activities, the name of the sharedpreference must be the same – Mohsen Nov 09 '19 at 12:53
but I still can't get the starting time from ```MainActivity``` ,the chronometer still start from 0:00 in the second activity – Anonymous Nov 09 '19 at 15:21
thats because you get startTime from chornometer.getBase() and thats 0:00 – Mohsen Nov 10 '19 at 08:53
i have edited the startTime in main activity to ```(SystemClock.elapsedRealtime() - chronometer.getBase());``` but the chronometer in second activity still remain zero but when i added a textview to check if the value is actually passed from main activity to second activity, it does. So I don't really know why it doesn't work when it comes to chronometer. I have updated the code could you please have a look? – Anonymous Nov 12 '19 at 09:55

How to save chronometer time and retrieve it in another activity using sharedpreferences

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